Structural member



Dec. 11, 1934- F. HIMMEL ET AL STRUCTURAL MEMBER Filed Jan. 6, 1934 Patented Dec. 11, 1934 UNITED STATES PATENT OFFICE STRUCTURAL MEMBER Application January 6, 1934, Serial No. 705,528 7 Claims. (0]. 29-181) This invention relates to improvements in structural members, and more particularly to structural members having an outer surface of stainless steel.

Of late years structural membersfor visible portions of building and store front constructions have commonly been made of stainless alloys containing iron and chromium or iron, chromium and nickel, and commonly spoken of as stainless steels. To meet the commercial requirements of the situation, it is necessary to supply such structural members with a highly-burnished surface. Owing to the tough, hard surface of stain: less steels, it takes considerable power or energy to properly burnish the surface. And this high burnishing power or energy applied to the surface develops considerable heat on the surface being burnished. Moreover, inasmuch as stainless steels have unusually low heat conductivity, the heat developd by burnishing is not readily conducted away or dissipated, but rather tends to accumulate at the portion of the structural member being burnished, with consequent considerable rise in temperature, which at some portions of the burnished surface becomes so great as to burn or cloud the surface and produce waves and buckles in the surface, thus damaging the finished product.

It is an object of this invention, therefore, to overcome the foregoing described disadvantages of an all-stainless steel construction. We have found that this can be accomplished by forming each of such structural members of an outer surface member of stainless steel and a backing member of relatively-higher heat-conductivity metal.

With the above and other objects in view, this invention includes the improved features and combinations of features disclosed in the following description, appended claims and accompanying drawing forming a part of this specification.

In the accompanying drawing inwhich one way of carrying out the invention is shown for illustrative purposes:

The figure of the drawing is a perspective view of a short length of a structural member made in accordance with this invention.

Referring to the drawing, is a structural member such as a moulding or bar which may be a used on store fronts, for example.

The front or outer surface member 11 is of stainless steel,

and the inner or backing member 12 is of a metal or alloy having relatively-higher heat conductivity than the front or outer member 11, such, for example, as aluminum, aluminum alloy, copwhich can be burnished by rapid-bumishing per, bronze, brass or other metal suitable for the purpose.

We preferably make the outer surface member of stainless steel or iron known commercially as 18-8, meaning that it is an alloy of iron containing 18 per cent of chromium and 8 per cent of nickel, which alloy is non-magnetic, although other stainless steel and iron alloys can be used. We find that an alloy of aluminum and manganese, preferably having about 97 per cent aluminum and about 3 per cent manganese provides a very effective backing member which has relatively-higher heat conductivity and is strong and light in weight.

In the structural member 10 illustrated in the drawing, the outer surface member 11 is about one-fourth as thick as the inner backing member 12, their thicknesses being, respectively, about .008" and '.032".

Although the structural member may be made in various ways, we prefer to make it by taking two strips of sheet metal, one for the outer member 13. and the other for the inner member 12, and simultaneously rolling or pressing them to the desired shape in contact with each other. The strip for the outer member 11 preferably has its sides 13 and 14 extend beyond the side edges of the inner member 12 and has its sides 13 and 14 folded over the side edges of the member 12, the sides 13 and 14 preferably being pressed somewhat into the sides of the inner member 12. It is not necessary to solder or weld the members 11 and 12 to each other inasmuch as the pressure of the burnishing wheel against the member 11 presses the portion of the member lLbeing burnished, into intimate contact against the member 12, thus affording good heat-conducting contact between the members 11 and 12. The member. 12 being of relatively-higher heat conductivity, rapidly conducts the heat along itself, thus distributing the heat and preventing any harmful rise of temperature of the member 11, even when the member 11 is subjected to heavy, rapid-burnishing pressure, thus providing an effective construction methods without burning or clouding the burnished outer surface of the member 11 or causing buckles therein. I

The invention may be carried out in other specific ways than that herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiment is therefore to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

We claim: a

1. A structural member having: an outer surface'member of stainless sheet steel having'its outer surface burnished; and an inner backing member of metal high in aluminum.

2. A structural member having: an outer surface member of stainless sheet steel having its outer surface burnished; and an inner backing member of aluminum-manganese alloy high in aluminum...

3. A sheet-metal structural member having: an outer surface member of stainless sheet steel having its outer surface burnished and an inner backing member of sheet-metal high in aluminum.

'4. A sheet-metal structural member having: an outer surface member of stainless sheet steel having its outer surface burnished; and an inner backing member of sheet, aluminum-manganese alloy high in aluminum.

5. A sheet-metal structural member having: an outer surface member of stainlesssheet steel having its outer surface burnished; and an inner backing; member of relatively-higher heat-con- 6. A sheet-metal structural member having: an outer surface member of stainless sheet steel having its outer surface burnished; and an inner backing member of relatively-higher heat-conductivity non-ferrous sheet metal, said outer and inner members being of substantially the same shape and having substantially all portions of their juxtaposed surfaces closely adjacent each other.

7. The method of manufacturing a sheet-metal structural member comprising: simultaneously rolling or. pressing together to a desired .shape, an outer surface member of stainless sheet steel and an inner backing member of relatively-higher heat-conductivity sheet-metal with substantially all portions of the juxtaposed surfaces of the outer and inner members closely adjacent each other, and folding the side edges of the outer member over the side edges of the inner member to secure the members together without solder,

welding'or the like; and burnishing the outersurface of said outer member by a burnishing wheel, the bumishing pressure of said burnishing wheel serving to successively press portionsof said outer member being burnished, into intimate contact with said inner member, whereby said inner mem ber dissipates the heat of burnishing from said outer memberand prevents buckling, burning or clouding of the outer surface thereof. 7

FRED HIMMEL. ISIDORE HIMMEL. 

